Industrial diamonds have been widely and successfully used in a number of downhole applications. They have been used, for example, to provide superabrasive drilling surfaces to afford improved performance of various downhole tools and components, including earth-boring tools for forming boreholes in subterranean earth formations for hydrocarbon production, carbon dioxide sequestration, etc. Diamonds have generally been used to provide cutting elements by securing them to a body. For example, fixed-cutter earth-boring rotary drill bits (also referred to as “drag bits”) include diamond cutting elements that are fixed to a bit body of the drill bit. Similarly, roller cone earth-boring rotary drill bits may include various diamond components in cones that are mounted on bearing pins extending from legs of a bit body such that each cone is capable of rotating about the bearing pin on which it is mounted. A plurality of diamond cutting elements may be mounted to each cone of the drill bit.
In particular, polycrystalline diamond compacts (PDCs) formed of small (e.g., micron-sized) diamond grains fused and bonded together by a high temperature, high pressure process using a metal catalyst, and supported on a ceramic substrate, have been used as downhole cutting elements. PDC drill bits have been found to provide a superabrasive abrasive surface which is capable of cutting through hard rock for extended periods of time, and under severe downhole conditions of temperature, pressure, and corrosive downhole environments, while maintaining the integrity and performance of the drill bit.
PDC cutting elements in which the catalyst material remains in the diamond table are generally thermally stable up to a temperature of about 750° C., although internal stress within the cutting element may begin to develop at temperatures exceeding about 400° C. from phase changes in the metal catalyst (e.g., cobalt, which undergoes a transition from the beta-phase to the alpha-phase) and/or differences in the thermal expansion of the diamond grains and the catalyst metal at the grain boundaries. Hence, over time, such PDC drill bits are still subject to cumulative failure modes. In the course of drilling, cutting elements can wear, fracture, or accumulate damage that can alter, limit, or significantly degrade their performance in downhole applications.
Thus, it is desirable to provide diamond compositions that promote improved nucleation and growth of the micron-sized diamond grains used to form the PDC's and that may also be used to reduce the internal stresses associated with the metal catalyst retained in the polycrystalline diamond microstructure, as well as methods of making these diamond compositions. In view of the many desirable properties of diamond, it is also desirable to provide diamond compositions that may be used for other applications, including various fluids, abrasives, coatings and other powder compact applications.